To help Mum
and Dad decide what to buy, you are going to design an experiment to investigate
what is required to grow healthy cress. Then you will find out how 'pollutants'
in the air and water affect their growth.
When you have
finished your experiments, you can write a letter to the manager of your local
supermarket with advice on how to decide which suppliers to get his/her cress
from. It would be brilliant if your letter included a 'Digital Diary' of how
the plants grew in different conditions, as this would give the manager lots
of valuable information.